LIcence question about statically linking Qt5 with my Android App



  • Hi all,

    I have kinda skimmed through this page, but I don't really understand it: http://wiki.qt.io/Licensing-talk-about-mobile-platforms

    My question is, can I make a QML based app in my community edition qt5 creator, and statically link it and build it for the Android Play store, and then can I release it on the play store?

    I don't want to buy Qt5, but want to release an app on Android Play store; an app that is closed source. Am I allowed to do that with static linkage?

    I saw in the showcase section that a lot of people have released their apps using Qt5 on Google Play store, but I am not sure whether they are using community edition or paid edition. So I thought I'd ask here .

    Thank you.



  • First of all: I'm not a lawyer.
    From the LGPL FAQ (https://www.gnu.org/licenses/gpl-faq#LGPLStaticVsDynamic):

    Does the LGPL have different requirements for statically vs dynamically linked modules with a covered work? (#LGPLStaticVsDynamic)
    For the purpose of complying with the LGPL (any extant version: v2, v2.1 or v3):

    (1) If you statically link against an LGPL'd library, you must also provide your application in an object (not necessarily source) format, so that a user has the opportunity to modify the library and relink the application.

    (2) If you dynamically link against an LGPL'd library already present on the user's computer, you need not convey the library's source. On the other hand, if you yourself convey the executable LGPL'd library along with your application, whether linked with statically or dynamically, you must also convey the library's sources, in one of the ways for which the LGPL provides.

    Hope that helps!



  • Thank you. The part in section 1 here is interesting. But it raises the question: so I can statically link against Qt library and release the app, as long as I also provide my app in a format that loads the Qt library at runtime? So I could conceivably release the statically linked application on the App Store, and also release the dynamically linked application on my website or somewhere else. Or I could release both formats on the app store, and promote only the statically linked one.

    Not sure if that's how people do it with their Qt apps.



  • You could also release your statically linked application to the app store and put a link in your about text that points to place where interested people can download your object files and a linker script that allows them to link your app as they wish.


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